1. Field of the Invention
The present invention relates to a display device and a method of manufacturing a display device, and more particularly, to a liquid crystal display device and a method of manufacturing a liquid crystal display device.
2. Discussion of the Related Art
A liquid crystal display (LCD) device displays images by controlling light intensity through a liquid crystal material injected between two thin substrates. The light intensity is controlled by changing orientation of liquid crystal molecules of the liquid crystal material by inducing an electric field to the liquid crystal molecules. The electric field is created by supplying a voltage to a pixel electrode formed on one of the two thin substrates and supplying a voltage to a common electrode formed on another one of the two thin substrates. Presently, LCD devices are commonly used for electronic instruments, such electronic watches, liquid crystal TVs, and notebook computers, and in transportation devices, such automobiles and airplanes.
FIG. 1 is a cross sectional view of a liquid crystal cell according to the related art. In FIG. 1, a liquid crystal cell includes an array substrate 110 having a TFT and a pixel electrode aligned thereon, a color filter substrate 120 having a color filter and a common electrode aligned thereon, and a liquid crystal material between the array and color filter substrates 110 and 120. The liquid crystal cell is manufactured by forming an alignment layer for aligning liquid crystal molecules of the liquid crystal material layer, bonding the array and color filter substrates 110 and 120 together to maintain a uniform gap, cutting the bonded substrates into a plurality of unit cells, and injecting the liquid crystal material into the gap between the bonded substrates.
However, failure of the picture quality may occur depending on the locations on the LCD device when the cell gap is not uniform since the transmittance of the light passing through the region is varied spatially, which turns out to be a more serious problem with a large-sized liquid crystal panel. Accordingly, the cell gap formation process includes depositing a seal line 130 on the array substrate 110 before being bonded with the color filter substrate 120, which has spacers scattered thereon. Then, the liquid crystal material is injected into the cell gap and the seal line 130 is sealed.
FIGS. 2A to 2C are plan views of a seal pattern according to the related art. In FIG. 2A, when an upper substrate is not yet bonded to a lower substrate, a seal line is configured to comprise a single line of sealant with a liquid crystal injection hole.
In FIG. 2B, when the upper and lower substrates are bonded together, any air surrounded by the seal line must be vented and made to flow through the liquid crystal injection hole. Accordingly, air pressure through the liquid crystal injection hole significantly increases. Thus, any spacers scattered between the bonded substrates will be dislodged. As a result, the gap between the bonded substrates will not remain uniform. Moreover, in order to compensate for the increase of air pressure through the liquid crystal injection hole, pressure applied to the two substrates must be increased, thereby possibly damaging the substrates. In addition, the damaged substrates problem becomes more serious when the substrates are enlarged.
In FIG. 2C, when the substrates have been bonded, a width of the seal line increases and a width of the liquid crystal injection hole decreases.